1. Field of the Invention
The present invention generally relates to a refueling system used in a fuel tank of an automobile. More specifically, the present invention relates to an automobile refueling system that has a simplify layout and that decreases manufacturing cost by eliminating a vent valve and reducing the number of parts, while enabling easy refueling.
2. Background Information
Various types of fuel tank refueling systems are known to be used for automobiles and other vehicles. One example of a fuel tank refueling system has a filler tube that directs fuel into the fuel tank is provided in the refueling port so as to face a tip opening. A filler cap is provided on the tip opening of the filler tube and serves to open and close the tip opening. A vent valve is provided on the upper wall section of the fuel tank. The vent valve is connected to a canister via a refueling control valve and a vent line. A vapor cut value is also provided in the upper wall section of the fuel tank. The vapor cut valve is connected to the canister via an engine vacuum cut valve and a fuel vapor line. The refueling control valve is connected to the vicinity the tip opening of the filler tube via a signal line. The upper wall section of the fuel tank communicates with the vicinity the tip opening of the filler tube via a recirculation line.
Next, the operation of this conventional refueling system will be described. With this conventional refueling system, the fuel vapor that is generated inside the fuel tank when the vehicle travels is discharged from the vent valve to the canister via the refueling control valve and the vent line. The cleaned gas that remains after the fuel components have been adsorbed by the canister are discharged to the atmosphere through the canister drain cut valve. When refueling is conducted, the filler cap of the filler tube is removed and a refueling nozzle is inserted through the opening of tip. Fuel flows down the filler tube into the fuel tank. A portion of the fuel inside the fuel tank becomes fuel vapor and is sent to the canister through the refueling control valve and the vent line. Some of this fuel vapor is circulated to the filler tube through the recirculation line. Then, the liquid surface of the fuel inside the fuel tank rises and reaches the bottom end of the recirculation line at the same time it reaches the bottom end of the vent valve. This causes the vent valve to close. Consequently, the pressure inside the fuel tank rises and the liquid surface of the fuel moves up the filler tube. The fuel activates an automatic stop mechanism provided on the refueling nozzle and refueling stops.
Another known refueling system of this type is disclosed in U.S. Pat. No. 4,714,172. The refueling system of this patent has a refueling control valve which is divided into two fluid chambers by a movable wall. The first chamber provides a closeable junction in the vapor recovery passageway between a liquid fuel tank and a vapor storage canister. The second chamber has a combined inlet/outlet, which is interconnected with a signal pressure region in the fuel tank filler tube adjacent to the filler tube cap. A valve plug is fixed to the movable wall so that when the pressure in the first fluid chamber, the signal pressure region and the second fluid chamber are substantially equivalent, the valve plug is positioned to close the vapor recovery passageway. When the closure cap is removed, a filler nozzle is inserted into the filler tube, and liquid fuel is being delivered into the fuel tank, the pressure in the signal pressure region and the second fluid chamber decreases relative to that in the tank and the first fluid chamber, the movable wall is displaced from its normal position causing the valve plug to open the vapor recovery passageway between the fuel tank and the vapor storage canister.
In view of the above, there exists a need for an improved refueling system that overcomes disadvantages in the prior art. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
It has been discovered that the above-mentioned refueling systems have complicated layouts that are expensive to manufacture. This is because the vent valve, which is obstructed by the rise of the fuel surface, is provided on the upper wall section inside the fuel tank.
The object of the present invention is to solve the aforementioned problems. Another object of the present invention is to eliminate the vent valve, and reduce the number of parts. Thus, the present invention provides a refueling system that can have a simplified layout and that can be relatively inexpensive to manufacture.
In order to achieve these objects, a refueling system is provided that basically comprises a canister, a canister drain cut valve, a fuel level detecting device, a refueling detecting device and a refueling controller. The canister is configured to adsorb and clean fuel vapor generated inside a fuel tank. The canister drain cut valve is operatively coupled to the canister and configured to discharge air cleaned by the canister. The fuel level detecting device is configured to be operatively coupled in the fuel tank to detect fuel level inside the fuel tank. The refueling detecting device is configured be operatively coupled in the fuel tank to detect if fuel is being delivered to the fuel tank. The refueling controller is configured to open the canister drain cut valve when the refueling detecting device detects that fuel is being delivered and to close the canister drain cut valve when the fuel level detected by the fuel level detecting device is greater than a first prescribed height.
These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.